Regulating system



945- R. A. GEISELMAN 2,390,735

,REGUL'ATING SYSTEM Filed Dec. 8, 1942 WITNESSES: INVENTOR Patented Dec.11, 1945 REGULATING SYS'lEli/I Ralph A. Geiselman, Wilkinsburg, Pa.,assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., acorporation of Pennsylvania Application December 8, 1942, Serial No.468,215

Claims.

This invention relates to electrical systems and, in particular, toregulating or limiting systems for synchronous condensers.

In electrical systems which utilize synchronous condensers connected toa power circuit, it has been quite difiicult to provide satisfactoryregulation of the synchronous condenser. Many different regulatingsystems have been developed for maintaining the voltage of suchdynamo-electric machines substantially constant. Likewise systems basedon the regulation of current have also been developed. All the systems,however, are not satisfactory, and in particular, the current regulatingsystem, since the voltage may fluctuate regardless of th currentregulation. Further, since the synchronous condenser is rated in kva, itis preferred to provide for regulating or limiting the kva. output ofthe machine.

It is an object of this invention to provide a system responsive tochanges in kva. for regulating or limiting the kva. of a synchronouscondenser.

Other objects of this invention will become apparent from the followingdescription when taken in conjunction with the accompanying drawing, inwhich:

Figure 1 is a'diagrammatic view of an embodiment of this invention forlimiting the kva. of a synchronous condenser; and

Fig. 2 is a diagrammatic view of a kva. regulating system forsynchronous condensers.

Referring to Fig. 1, a synchronous condenser I0 is connected toconductors l2, l4, and I6 of a three-phase power circuit and is providedwith a field winding l8 that is connected to an exciter generator 20.The exci-ter generator is provided with a field winding 22 that isconnected to be energized from the armature 24 of the exciter, asectional resistor 26 being connected in circuit therewith.

The section 28 of the resistor 26 is disposed to be shunted through thecontact members 30 and 32 of a relay 34 which is operated in accordancewith the operation of the regulator contact members 36 and 38. Thecontact member 38 is carried by an arm 40 of a bell crank lever 42 andis operated in accordance with the pull of a control electromagnet 44that is balanced by the with windings 54 and 55, respectively, connectedthrough resistors 58 and 60, respectively, to be energized in accordancewith the voltage of the power circuit [2, l4, and IS. A section 62 ofthe resistor connected in circuit with the Winding 56 of theanti-hunting electromagnet 50 is disposed to be shunted through thecontact members 64 and 86 of the relay 34.

The relay 34 illustrated is biased upwardly by the spring 68 and isprovided with a main energizing winding 10 and a neutralizing Winding12, the winding 70 being connected at all times to a suitable source ofpower, (not shown), whereas the winding 12 is disposed to be connectedto the same power source only upon en agement of the contact members 36and 38. The operation of the contact members 36 and 38 is primarilycontrolled by the electromagnets 44 and The spring tension member 52referred to hereinbefore is also connected to a depending arm 14 of aT-shaped lever 16 that is disposed to be actuated in accordance with theoperation of the electromagnet 18. A stop 15 is disposed in the path ofmovement of arm 14 to limit the movement of the lever 16 in the onedirection. The electromagnet 18 is of well known construction as shownand described in Patent No. 1,565,410, issued December 15, 1925, to C.A. Boddie, being provided with two series connected windings and 82 thatare connected through the rectifier 84 to a current transformer 86associated with the power conductor I 2 and a winding 88 connectedthrough the rectifier 90 to conductors l2 and N5 of the power circuit.The electro-magnet 18 is, therefore, by reason of the rectifiers 84 and98, disposed to be energized in accordance with the kva. of the powercircuit.

In operation, the excitation of the synchronous condenser I0 iscontrolled in accordance with the load supplied by the conductors l2, l4and I6. For normal operation, the synchronous condenser Ill is regulatedto maintain constant voltage. However, where the load is such that alagging current is encountered, then the synchronous condenser I0 isoverexcited to take a corresponding high value of leading current. Sincesynchronous condensers are usually rated in kva., the operation of thecondenser l0 when overexcited is controlled or limited by limiting thelagging kva. generated by the condenser while raising the kva. voltageto normal and producing a more leading power factor on the externalpower supply.

For normal operation, the excitation of the synchronous condenser isdependent upon the operation of the control electromagnet 44 and theanti-hunting electromagnet For such operations, the depending arml i oflever 16 seats against the stop-l5 to limit the movement of the lever inone direction.

The electromagnet 54 is thus normally energized by a circuit whichextends from power conductcr 12 through resistor 58 and the energizingwinding 54 of the electromagnet to the power conductor IS, theanti-hunting electromagnet 53 being similarly energized by a circuitwhich extends from the power conductor I2 through re.- sistor 60 and theenergizing winding 56 to the power conducto l6. It is evidentthat theweight 46 can be so adjusted that the magnetic pull of the coil 54 issuch as to substantially balance the weight 46 for any given voltageacross the con d'uctors, whereby the movable contact member 38 vibratesinto and out of engagement with the stationary contact member 3 5 toefiect a regulating action to maintain the required voltage.

As is evident from the drawing, the main wind ing ill of the relay 34 isenergized at all times by a circuit which extends from the positiveterminal of a constant source of power (not shown), through resistors IIand I3, the winding?!) to the negative terminal of the constant sourceof power to actuate the relay 34 downwardly against the bias of thespring ,68. When thus energized the contact members 32 and 64 of therelay 3% are'moved to a circuit opening position. When the movablecontact member 38 of the regulator is actuated into engagement with thecontact member 36, a circuit is established Which may be traced from thepositive terminal of a constant source of supply (not shown) throughresistors II and !5, contact members 38 and 33, neutralizing winding '12of the relay 34 to the negative terminal of the constant source ofpower. By energizing the neutralizing coil '52 the magnetic pull of themain winding is so neutralized that the springrfit associated with therelay 34 biases the relay upwardly to a position where its contactmembers 32 and 66 are in circuit closing position.

The movement of the contact member 32 to engage the contact members 30effectively shunts the resistorsection 28'from circuit with the fieldwinding 22 of the exciter 28 to increase the energization of the windingand thereby increase its output and effect an increase in theenergization of the field winding l8 of the synchronous condenser IU.Thus, the number and duration of the vibrations of the contact member 38into and out of engagement with the contact member 38 determines theaverage period of time during which the resistor section 28 is connectedin circuit with the field winding 22 of the excite 251 to control theenergization of the field winding is of the synchronous condenser l0.

If the voltage of the power circuit !2, l4, and I6 tends to Vary from arequired value, for example, tends to increase as'by reason of a lightload, the energization of the Winding 54 of e1ectromagnet 44 isincreased, effecting an upward movement, of the core of theelectromagnet to effect a pivotal movement of the lever 42 in aclockwise direction about its pivot to, in effect,

move the movable contact member 38 away from the stationary contactmember 36. The lengthmember 36, in effect, shortens the period of timeduring which the resistor section '28 is shunted,

thereby, in effect, increasing the average amount of resistance inseries circuit with the field winding 22 of'the eXciter 20 to decreasethe output of the exciter 20 and efiect a decrease inthe energization ofthe field winding it of the synchronous condenser. By reducing theenergization of the synchronous condenser field, the amount of leadingload taken by the condenser is increased,

causing the condenser to take a lagging load from the power conductors,thereby preventing a rise in voltage. V

At the same time that contact member 32 is in engagement with contactmember 39 to shunt the resistor section 28, the contact member 66 ofrelay 34 is actuated into engagement with the contact member 64 toestablish a circuit which may be traced from the power conductor I2through contact members 64 and (i5, resistor section 63 of the resistor60, and the energizing I winding 56 of electromagnet 53 to the powerconductor It to effect an increase in the energizetion of the actuatingwinding of relay 50. The increase in the energization of. the actuatingwinding of relay 50 causes the core member of the electromagnet to moveupwardly to permit the bell crank 48 to rotatein a counterclockwisedirection about its pivot point, and thereby, in

effect, further move the movable contact mem ber 38 away from itscooperating stationary contact member 36 to, in effect, further shortenthe period of time in which the resistor section 28 is shunted from thefield winding circuit of the eXciter 20. The operation of theelectromagnet 50 thus gives effective anti-hunting control of theoperation of the regulator. 1

If, on the other hand, the change in the voltage of the power conductorsl2, l4, and i6 is a decrease, then the Winding 540i electromagnet 44 isso deenergized that the lever 42 pivots in a counterclockwise directionto move the movable contact member 38 closer to its cooperatingstationary contact member 35 whereby the contact members are inengagement for a greater average period of time so that the averageamountoi' resistance connected in circuit with the field winding 22 isthereby decreasedto' effectively increase the energization of thewinding 22 and thereby, in effect, increase the energization of thefield winding 18 of the synchronous condenser I0.

If instead of normal loads the load is such .that an overexcitedcondition of the synchronous condenser is encountered, then theelectromagnet I8 is energized in accordance with the increase in thekva. of the power conductors. This increase in the energization of theelectromagnet 18 effects a counterclockwise movement of the T-shapedlever 16 to actuate the arm 14 away from the stop 15 and to apply a pullto the spring 52,'thereby, in effect, moving the lever 42 and themovablecontact member 38 carried thereon in a direction away from the fixedcontact member 36. As will be apparent, the movement of the contactmember 38, in effect, shortens the average-period of time in which thecontact members 38 and 36 are in engagement and thereby increases theaverage time in which the resistor section 28 is connected in seriescircuit with the field winding 22 of the excited. In other words, theaverage amount of resistance connected in series with the field winding22 is increased, whereby the energization of the field winding 22 isdecreased'to effect a decrease in the energization of the field windingI8 of the synchronous condenser l0. means of the clectromagnet 78, it ispossible to provide for limiting the: maximum' km; ofthe Thus, by

power circuit, the limit for which control is provided being determinedby the initial balance of the T-shaped lever I6, or, in other words, thebalance between the weight carried at one end of the lever I6 and themagnetic lift of the electromagnet 18 at the other end of the lever.Byreason of the rectifiers 84 and 90, it is evident that theelectromagnet 18 is directly responsive to the kva. of the powercircuit, being free of any eilects or the phase angle.

In the embodiment of this invention illustrated in Fig. 2, a variablerheostat 92 is connected in circuit with the field winding I8 of thesynchronous condenser I0, a motor 94 being provided for adjusting therheostat 92 through the gear drive 98. As illustrated, the rheostatmotor 94 is pro vided with an armature winding 98 and field windings Iand I02 disposed to be energized when the relays I 04 and I06,respectively, are energized to actuate their contact members I08 and H0,respectively, to a circuit closing position. One end of the energizingwindings H2 and H4 of the relays I04 and I06, respectively, is connectedto the stationary contact members I I6 and 8, respectively, of theregulating apparatus I20, the other end of each of the windings I I2 andI I4 being connected through a common lead to the negative terminal of aconstant source of supply (not shown).

The regulating apparatus I comprises electromagnets I22 and I24 actin onthe lever I26 which carries contact members I28 and I30, and which ismounted for pivotal movement against the bias of the adjustable spiralspring I32. Each of the electromagnets I22 and I 24 is provided with aplurality of windings, theseries connected current responsive windingsI34 and I36 of the elec tromagnet I22 being connected in series with theseries connected current responsive windings I38 and I40 of theelectromagnet I24, while the voltage responsive winding I42 ofelectromagnet I22 is connected in series circuit with the voltageresponsive winding I44 of electromagnet I24. The series connectedcurrent responsive windings of the electromagnets I22 and I24 aredisposed to be connected through the rectifier 84 to the currenttransformer 88 connected in circuit relation with the power conductorI2, while the series connected voltage responsive windings of theelectromagnets I 22 and I24 are connected through the rectifier 90 tothe power conductors I2 and I6.

In operation, the spring I32 is adjusted to balance the pull of theelectromagnets I22 and I24 for a predetermined kva. The windings of theelectromagnets are so wound that when energized the core member ofelectromagnet I22 tends to move downwardly, whereas the core member ofthe electromagnet I24 tends to move upwardly, this movement beingbalanced against the bias of the spring I32. If the system is beingoperated in conjunction with loads requiring a leadin correction factor,then as the kva. of the power circuit varies from the predeterminedvalue which is to be regulated, as, for example, if the kva. increases,each of the electromagnets I 22 and I24 is so energized as to actuatethe lever I26 against the bias of the spring I32 to effect acounterclockwise pivotal movement of the lever I28 to a position wherethe movable contact member I28 engages the stationary contact member H6.

The engagement of the contact members I28 and IIS thus establishes acircuit which can be traced from the positive terminal of the constantsource of supply (not shown) through the lever I26, contact members I28and H 8, winding I-I2-* of relay I04, to the negative terminal of thecon stant source of power to energize the winding I I2 and actuate therelay to a circuit closing position.

With the relay I04 actuated to its circuit closing position, a circuitis established which extends from the positive terminal of a constantsource of supply through the armature winding 98 of the rheostat motor,the field winding I00 contact members I08 of the relay I04 to thenegative terminal of the constant source of power to so energize therheostat motor 94 as to effect its opera- 1 tion to connect additionalsections of the rheostat 92 in circuit with the field winding I8 of thesynchronous condenser I0 to decrease the energization of the fieldwinding I8.

If, "on the other hand, the change in the'kva. of the power circuit is adecrease, then the energization of the electromagnets I22 and I24 is sodecreased as to effect a clock-wise movement of the lever I 26 about itspivot by reason of the: spring I32 to actuate the contact member I30into engagement with the fixed contact member II8. Engagement of thecontact members I3!)- and H8 establishes a circuit which extends fromthe positive terminal of the constant source of supply through the leverI26, contact members I30 and H8, winding II4 of the relay m0 to thenegative terminal of the constant source of supply to so energize thewinding II4 as to actuate the contact member IIO of relay I06 to itscircuit closing position.

With the contact member III] of relay Ifit in a circuit closingposition, a circuit is established extending from the positive terminalof a con-- stant source of supply through the armature winding 98 of therheostat motor 84, field winding I02, contact member Hi! to the negativeterminal of the constant source of supply to so energize the motor 94 asto operate the "field rheostat 92 to effect a decrease in the number ofsections connected in series circuit with the field winding I8 of thesynchronous condenser 50, and thereby effect an increase in theenergization of the synchronous condenser.

As will be apparent from the foregoing description with respect to Figs.1 and 2; the system of this invention provides effective control of theop-. eration of a synchronous condenser to maintain substantiallyconstant the kva. of the condenser.

It is, of course, possible that modifications be made in the systemsdisclosed without detracting from the essence of the invention, and itis, therefore, desired that this invention be not limited to theforegoing description except insofar as is necessitated by the scope ofthe appended claims.

I claim as my invention:

1. In an electrical system, the combination with a three-phase powercircuit, a dynamoelectric machine connected thereto, the dynamoelectricmachine having a field winding, a rheostat having a plurality ofresistor sections disposed to be connected in circuit relation with thefield winding to control the excitation of the dynamo-electric machine,means disposed to control the connections of the resistor sections, anelectromagnet having a pair of opposed current responsive windingsconnected in series circuit relation and a voltage responsive windingdisposed therebetween to cooperate in controlling the operation of saidcontrol means, and rectifiers connected between the electromagnet andthe three-phase power circuit to render the electroeIectric machineconnected thereto, the dynamoelectric machine having a field winding, arheostat having a pluralit of resistor sections disposed to be connectedin circuit relation with'the field winding to control the excitation ofthe dynamo-electric machine, means disposed to control the connectionsof the resistor sections, a regulator disposed to control the operationof said control means, the regulator including an electromagnet having apair of opposed current responsive windings connected in series circuitrelation and a voltage responsive winding disposed therebetween tocooperate in determining the operation of the regulator, and rectifiersconnected in circuit with the windings of the electromagnet and thethree-phase power circuit to render the regulator responsive to thekilovoltamperes of the dynamo-electric machine to so control theoperation of the control means as to maintain the kilovolt-ampere outputof the dynamo-electric machine substantially constant.

3. In an electrical system, the combination with a three-phase powercircuit, a dynamoelectric machine connected thereto, the dynamoelectricmachine having a field winding, a rheostat having a plurality ofresistor sections disposed to be connected in circuit relation with thefield winding to control the excitation of the dynamo-electric machine,means disposed to control the connections of the resistor sections, anelectromagnet having a pair of opposed current responsive windingsconnected in series circuit relation and a voltage responsive windingdisposed therebetween to coooperate when energized to control theoperation of said control means, and a rectifier connected between eachof the current responsive and voltage responsive windings and thethree-phase power circuit, the electromagnet thereby being responsive tothe kilovolt-amperes of the dynamo-electric machine for controlling thekilovolt-ampere output of the machine.

4. In an electrical system, the combination with a three-phase powercircuit, a dynamo-electric machine connected thereto, the dynamoelectricmachinehaving a field winding, a rheo. stat'having 'a' plurality-ofresistor sections dis-.

electromagnets having core members disposed in spaced relation. formovement to control the pivotal movement of the lever, currentresponsive windings disposed on each of the core members connected inseriescircuit relation,voltage responsive windings disposed on each ofthe core members connected in series circuit relation, the current andvoltage responsive windings being disposed to be energized from thethree-phase power source to actuate the core members in oppositedirections, and a rectifier connected in each of the current and voltageresponsive winding circuits to provide in phase energizing componentsfor each of the electromagnets, the electromagnets thereb beingresponsive to the kilovolt-amperes of the dynamo-electric machine tomaintain the kilovolt-ampere output of the machine substantiallyconstant. A

5. In an electrical system, the combination with a three-phase powercircuit, a dynamo electric machine connected thereto, the dynamoelectricmachine having a field winding, a rheostat having a pluralit of resistorsections disposed to be connected in circuit relation with the fieldwinding to control the excitation of the dynamo-electric machine, andmeans including electromagnetic means disposed to control theconnections of the resistor sections, the electromagnetic means having apair of opposed current responsive windings connected in series circuitrelation and a voltage responsive winding disposed therebetwecn, andrectifiers connected in circuit between the current responsive windingsand the voltage responsive winding of the electromagnetic means and thethree-phase circuit, the electromagnetic means thereby being responsiveto the kilovolt-amperes of the dynamoelectric machine to control theconnections of the resistor sections and thereby control thekilovolt-ampere output of the dynamo-electric machine.

RALPH A. GEISELh/IAN.

